This would be nice feature and improve desktop workflow for those of us that leave chat open somewhere almost all the time.

It might also be useful to cause the chat app to switch to the room that generated the ping when the room was focused using the desktop notification. Additionally, the same highlight/focus action that happens when following a backref should be triggered so that you go straight to the message that initiated the ping.

Clicking the notification will now open/show/focus the chat window that generated the notification. Note that if you have multiple tabs/windows open with chat rooms, the choice of which tab to focus may seem rather arbitrary (it will generally be the one that has been open the longest).